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Covid-19: efficiency, storage … Four questions about Moderna’s vaccine

Moderna’s vaccine candidate, estimated to be close to 95% effective, was designed with technology similar to that of the Pfizer / BioNTech alliance.

Will we have a vaccine from the first months of 2021? It is more and more likely. After Pfizer / BioNTech last week, the American biotechnology company Moderna announced on Monday that its vaccine candidate, mRNA-1273, is 94.5% effective.

This vaccine is also in addition to the solutions developed by the Chinese and the Russians, already approved in their respective countries. This 94.5% efficiency is, for the moment, the highest rate reported in the world, ahead of Pfizer / BioNTech (90%) and Sputnik-V (RDIF, Russia, 92%). Moderna’s result means that the risk of falling ill with Covid-19 was reduced by 94.5% between the placebo group and the vaccinated group of the large clinical trial underway on 30,000 people in the United States, according to a preliminary analysis of the very first cases: in this case, 90 participants in the placebo group contracted Covid-19, compared to 5 in the vaccinated group.

  • What technology is used?

As with the Pfizer / BioNTech vaccine, it is the recent “messenger RNA” technology that has been favored. This aims to train our immune system to recognize the coronavirus, to raise its defenses preventively, in order to neutralize the real virus if it were to infect us. How? ‘Or’ What ?

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Laboratories inject strands of genetic instructions called messenger RNA into the body, which is the molecule that tells our cells what to make. Every cell is a mini-factory of proteins, according to the genetic instructions contained in the DNA of its nucleus (DNA is transcribed into RNA when needed). This messenger RNA – made in the laboratory – is inserted and hacked into this machinery to make proteins or “antigens” specific to the coronavirus: its “spicules” (“spikes”), these so recognizable points which adorn its surface and allow it to attach to human cells in order to penetrate them. These proteins, harmless in themselves, will be released by our cells and delivered to the immune system, which will then produce antibodies.

  • Are there any differences with other vaccines?

At no time is the SARS-CoV-2 virus, even inactivated, injected, and the RNA cannot integrate into our genome. Conventional vaccines can be made from inactivated (polio, influenza), attenuated (measles, yellow fever) viruses, or just proteins called antigens (hepatitis B).

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Chinese companies Sinovac Biotech and Sinopharm have chosen the first method, that of “inactivated” viruses. Russia, which has announced an efficiency of 92% for its Sputnik vaccine, for its part uses a “viral vector” vaccine, using a transformed virus to add part of the one responsible for Covid-19.

  • What more do we know about this vaccine candidate?

Unlike Pfizer / BioNTech, some additional data has been provided by Moderna about its vaccine against Covid-19. First, no serious patient with Covid-19 was recorded among the vaccinated people, against 11 in the placebo group. Two doses, several weeks apart, are required, as with Pfizer / BioNTech serum.

In total, about 9-10% of those vaccinated experienced fatigue and muscle pain after the second dose, and a lesser proportion of other side effects including headache (4.5%) and redness around the spot. injection (2%).

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It is not yet clear how long the vaccine lasts, which only time will tell. Stéphane Bancel, CEO of Moderna, welcomed the announcement, also specifying that the first clinical indications of the vaccine can “prevent the disease of Covid-19, including the severe form”.

  • How will it be distributed and stored?

Moderna, in its press release, announces storage of the vaccine for up to 30 days at a temperature of 2 ° to 8 °. It will remain stable at -20 ° for transport or long storage, of the order of six months. The laboratory stands out from Pfizer / BioNTech in this area, the alliance having announced Monday a storage at -70 °. In fact, Moderna’s vaccine could be more easily distributed to pharmacies and doctors’ offices.

Moderna intends to manufacture 20 million doses by the end of December. The company received $ 2.5 billion from the US government to develop the vaccine, and produce 100 million doses. Moderna has also signed contracts with Canada, Switzerland, Japan, Israel and Qatar and is in negotiations with the European Union, the United Kingdom and the international Covax program. The market demand is expected, like its American competitor, within the next few weeks.

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